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Anonymity on the internet is a very fragile thing; every anonymous online identity on this planet is only about 31 bits of information away from being completely exposed. This is because the total number of internet users on this planet is about 2 billion, or approximately 2^{31}. Initially, all one knows about an anonymous internet user is that he or she is a member of this large population, which has a Shannon entropy of about 31 bits. But each piece of new information about this identity will reduce this entropy. For instance, knowing the gender of the user will cut down the size of the population of possible candidates for the user's identity by a factor of approximately two, thus stripping away one bit of entropy. (Actually, one loses a little less than a whole bit here, because the gender distribution of internet users is not perfectly balanced.) Similarly, any tidbit of information about the nationality, profession, marital status, location (e.g. timezone or IP address), hobbies, age, ethnicity, education level, socio-economic status, languages known, birthplace, appearance, political leaning, etc. of the user will reduce the entropy further. (Note though that entropy loss is not always additive; if knowing X removes 2 bits of entropy and knowing Y removes 3 bits, then knowing both X and Y does not necessarily remove 5 bits of entropy, because X and Y may be correlated instead of independent, and so much of the information gained from Y may already have been present in X).

One can reveal quite a few bits of information about oneself without any serious loss to one's anonymity; for instance, if one has revealed a net of 20 independent bits of information over the lifetime of one's online identity, this still leaves one in a crowd of about 2^11 ~ 2000 other people, enough to still enjoy some reasonable level of anonymity. But as one approaches the threshold of 31 bits, the level of anonymity drops exponentially fast. Once one has revealed more than 31 bits, it becomes theoretically possible to deduce one's identity, given a sufficiently comprehensive set of databases about the population of internet users and their characteristics. Of course, such an ideal set of databases does not actually exist; but one can imagine that government intelligence agencies may have enough of these databases to deduce one's identity from, say, 50 or 60 bits of information, and even publicly available databases (such as what one can access from popular search engines) are probably enough to do the job given, say, 100 bits of information, assuming sufficient patience and determination. Thus, in today's online world, a crowd of billions of other people is considerably less protection for one's anonymity than one may initially think, and just because the first 20 or 30 bits of information you reveal about yourself leads to no apparent loss of anonymity, this does not mean that the next 20 or 30 bits revealed will do so also.

Restricting access to online databases may recover a handful of bits of anonymity, but one will not return to anything close to pre-internet levels of anonymity without extremely draconian information controls. Completely discarding a previous online identity and starting afresh can reset one's level of anonymity to near-maximum levels, but one has to be careful never to link the new identity to the old one, or else the protection gained by switching will be lost, and the information revealed by the two online identities, when combined together, may cumulatively be enough to destroy the anonymity of both.

But one additional way to gain more anonymity is through deliberate disinformation. For instance, suppose that one reveals 100 independent bits of information about oneself. Ordinarily, this would cost 100 bits of anonymity (assuming that each bit was a priori equally likely to be true or false), by cutting the number of possibilities down by a factor of 2^100; but if 5 of these 100 bits (chosen randomly and not revealed in advance) are deliberately falsified, then the number of possibilities increases again by a factor of (100 choose 5) ~ 2^26, recovering about 26 bits of anonymity. In practice one gains even more anonymity than this, because to dispel the disinformation one needs to solve a satisfiability problem, which can be notoriously intractible computationally, although this additional protection may dissipate with time as algorithms improve (e.g. by incorporating ideas from compressed sensing).﻿

"During the second half of the 19th century, the world's biggest economies endured a series of brutal recessions. At the time, most forms of reliable economic knowledge were organized within feudal, patrimonial, and tribal relationships. If you wanted to know who owned land or owed a debt, it was a fact recorded locally—and most likely shielded from outsiders. At the same time, the world was expanding. Travel between cities and countries became more common and global trade increased. The result was a huge rift between the old, fragmented social order and the needs of a rising, globalizing market economy.

"To prevent the breakdown of industrial and commercial progress, hundreds of creative reformers concluded that the world needed a shared set of facts. Knowledge had to be gathered, organized, standardized, recorded, continually updated, and easily accessible—so that all players in the world's widening markets could, in the words of France's free-banking champion Charles Coquelin, "pick up the thousands of filaments that businesses are creating between themselves."

"The result was the invention of the first massive "public memory systems" to record and classify—in rule-bound, certified, and publicly accessible registries, titles, balance sheets, and statements of account—all the relevant knowledge available, whether intangible (stocks, commercial paper, deeds, ledgers, contracts, patents, companies, and promissory notes), or tangible (land, buildings, boats, machines, etc.). Knowing who owned and owed, and fixing that information in public records, made it possible for investors to infer value, take risks, and track results. The final product was a revolutionary form of knowledge: "economic facts."

"Over the past 20 years, Americans and Europeans have quietly gone about destroying these facts. The very systems that could have provided markets and governments with the means to understand the global financial crisis—and to prevent another one—are being eroded. Governments have allowed shadow markets to develop and reach a size beyond comprehension. Mortgages have been granted and recorded with such inattention that homeowners and banks often don't know and can't prove who owns their homes. In a few short decades the West undercut 150 years of legal reforms that made the global economy possible.

"The results are hardly surprising. In the U.S., trust has broken down between banks and subprime mortgage holders; between foreclosing agents and courts; between banks and their investors—even between banks and other banks.

..."We are now staring at a legal and political challenge. A legal challenge because American and European governments allowed economic activity to cross the line from the rule-bound system of property rights, where facts can be established, into an anarchic legal space, where arbitrary interests can trump facts and paper swirls out of control. The rule of law is much more than a dull body of norms: It is a huge, thriving information and management system that filters and processes local data until it is transformed into facts organized in a way that allows us to infer if they hang together and make sense."﻿

So with even a $399 tablet doing 2560x1600 pixel displays, can we please just make that the new standard laptop resolution? Even at 11"? Please. Stop with the "retina" crap, just call it "reasonable resolution". The fact that laptops stagnated ten years ago (and even regressed, in many cases) at around half that in both directions is just sad.

I still don't want big luggable laptops, but that 1366x768 is so last century. Christ, soon even the cellphones will start laughing at the ridiculously bad laptop displays.

And the next technology journalist that asks you whether you want fonts that small, I'll just hunt down and give an atomic wedgie. I want pixels for high-quality fonts, and yes, I want my fonts small, but "high resolution" really doesn't equate "small fonts" like some less-than-gifted tech pundits seem to constantly think.

In fact, if you have bad vision, sharp good high-quality fonts will help. #noexcuses﻿

these are the "sew outs" or previews we get before we give the "GO" for the badges. today was ohm's law and xbee. we worked with the folks form digi to get approval and for ohm's law +john de cristofaro gave us some good ideas.

You go to a mechanic and ask for an estimate to fix your car. He says, "well, we charge by the wrench-turn. It's a buck for every ten turns."

"Wrench-turns? That seems odd. What exactly is a wrench-turn?"

"A wrench-turns is two radians."

"What? I just want to get my car fixed!"

"Well, wrench-turns are what we can count easiest—all our wrenches and power tools have meters on them, see, calibrated and audited, and so that's what we charge for. You'll get an itemized bill showing exactly which tools used how many wrench-turns at what time."

"Huh. Okay, so what's a typical number of, uh, 'wrench-turns' to fix this?"

"Here's a list of common types of customers and how many wrench-turns they average. Looks like for you, we say it averages a thousand wrench-turns."

"So a hundred bucks? I was willing to pay about $150. What about parts?"

"Parts are just capital costs to facilitate wrench-turns."

"Really? Great! I was afraid I wouldn't be able to get my car fixed this month if it was going to cost more than $150. I'm glad to hear that this thousand 'wrench-turns' only costs a hundred bucks."

"So long as you don't use more than your limit of parts, that is."

"My limit?"

"You get three parts. After that there's a surcharge."

"Is three enough?"

"For most customers we find it's plenty. Our customers with special needs may need more."

"For your convenience, this contract authorizes us to bill you for the number of parts needed to fix your car. You don't have to do anything."

"What? I'm signing up for a hundred dollars but, without my prior knowledge, could end up owing up to a thousand bucks?"

"No, not up to a thousand dollars."

"Oh, that's a relief. There's a cap?"

"You said $1000. It's a surcharge in addition to the wrench-turn cost. If you used a fourth part, and a thousand wrench-turns, that would be eleven hundred dollars."

"Doesn't a $1000 seem like an awfully harsh penalty?"

"It's not a penalty, it just reflects our costs. It could be a new engine and we won't charge you any more. You're getting a very good deal."

"A new engine?!? But I don't need a new engine! You're saying I'd only have to pay that ridiculous figure if I used a fourth part, but do you think I'll need a fourth part?"

"Most of our customers don't need more than three parts."

"Most of the customers with a problem and a car like mine?"

"That's an average across all our customers."

"So, would that include customers who come in for an oil change or to get fluids topped up?"

"Yes."

"I see. And if you needed a nut, a bolt, and a washer... that would be one part?"

"No, that's three parts." He counts on his fingers. "Nut, bolt, and washer."

"Whoah. And so if you needed a single extra part, even one, I'd suddenly owe $1100."

"If you used a fourth part, the total with overage, yes. And if you used a fifth part, $2100. That's assuming you use a thousand wrench-turns, of course."

"Of cou... wait a second. What if this job took twenty thousand wrench-turns and no parts? Would it cost me $2000?"

"That's right."

"Do some jobs take that many?"

"Some customers find they need the sort of service that twenty thousand wrench-turns provide."

"Okay, I just can't agree to this. The idea of this open-ended contract where I don't know what's being used until I get the bill, where my expectation is of a reasonable cost, but where it can quickly escalate to... thousands of dollars! I think I need to go speak to another mechanic who doesn't charge this way. It's mad."

"You'll find that we all charge this way. Our outlays are very high; before we can service even the first customer, we have to have a garage, and hydraulics, and tools. And the metering and billing system is very expensive. This is the fairest way for you to share the costs, since you're paying for the wrench-turns you use, and no more."

"Wait! We do find that the rare customer finds that the metered pay-for-service contract model is not for them. For such customers, we do provide alternatives."

"I'm listening."

"You can pre-pay for only ten percent more. Pay $110, and when we reach a thousand wrench-turns, or need to use a fourth part, we will stop work until you pay for a recharge."

"Well, at least that way it isn't open-ended. And you'll call me when that happens so I can pay more?"

"For your convenience, at any time you can check the garage, and if you don't see us working on your car, you can come into the office and pay for a recharge."

"Um. Okay.... Will you give me an estimate of how much more work is remaining when I pay for more?"

"That's the convenient thing about this plan for our customers, there are no estimates! When you pay another $110, you get another hundred wrench-turns, and you also get topped off to three additional parts."

"So then I'd have six parts."

"Three additional parts. If we hadn't used any parts up to that point when you recharged, you'd still have three parts remaining. If you had used three parts, you'd get three more parts. It's all for your convenience so you don't have to think about it."

"But..."

"Yes?"

"Um... I'm actually not sure. That almost sounds reasonable... but something still bothers me about it."

"Many of our customers find the pre-paid plan right for them, even if they could pass the credit check for other services."

"You didn't mention the credit check. But that's not what was bothering me, I just can't quite put my finger on it. Wait! What if I know this job is going to take five parts, but they're cheap parts?"

"Well, we do have another option. It's much less efficient and we'd rather our customers not use this because it can encourage them to use more service than they need—"

"—more than I need? What on earth do you mean by that? What I need is for my car to get fixed. Never mind, I don't want to know. Go on."

"—but we do offer unlimited service plans."

"Oh? How much is it?"

"How much is what?"

"Your unlimited service plan."

"Which one?"

"— Which — oh, for pity's sake, why am I still talking to you? ...I guess I'll bite. I think I'm going to regret it, though. How can there be more than one unlimited service plan?"

"It just depends on how much service you want to be unlimited. Do you want a plan with a thousand wrench-turns and three parts, five thousand wrench-turns and ten parts, or ten thousand wrench-turns and eighteen parts?"

"But you said it was unlimited!"

"It is unlimited. Up to those amounts."

"And when you go over the limit?"

"It's an unlimited plan, there is no limit."

"You said it's unlimited up to those amounts."

"Yes, those are the defined plan service levels."

"Not limits."

"It's an unlimited plan."

"You're mad. You're absolutely mad, do you know that? So what happens when you go over the... what did you call it? Your not-limits?"

"The defined plan service level. It depends on whether it's wrench-turns or parts. In the case of parts, each additional part costs $1000."

"A thousand... but that's the same as the other options!"

"Pending credit check, it does not include the additional 10% convenience fee for the pre-paid option."

"Right. But how can you call it 'unlimited' then?"

"It's unlimited wrench-turns."

"But you said it's a defined something or other. What if I go with the thousand-turn plan, what if you need to use two thousand turns?"

"After a thousand turns, you'll continue to get our great wrench-turn service, merely at a reduced speed."

"What reduced speed?"

"You'll get the superior service of one wrench-turn every minute."

"Is that a lot? How many turns do you do per minute before I get to the limit?"

"There is no limit with the unlimited plans."

"Ugh! The... defined..."

"The defined service level? Under the defined service level, those wrench-turns we do at up to a hundred per minute."

"A hundred! So if my repair takes two thousand turns, and I do the pre-paid or the fee-for-service or the bigger..." You wince. "...'unlimited' plans, it'll be done in twenty minutes, but with the thousand-turn plan it'll take over sixteen hours? Three days, assuming you work on it eight hours a day?"

"Speeds up to a hundred wrench-turns per minute. It could take longer. Most customers see an average of fifty wrench-turns per minute up to their defined service levels."

"I see. But that's still forty minutes versus three days. I guess to be on the safe side I'd better go with the five-thousand plan. How much does that cost?"

"Five hundred dollars."

"$500! But that's how much the fee-for-service would be, and I may not even use five thousand turns!"

"At fee-for-service, you'd pay more for additional wrench-turns. With this plan, you get unlimited wrench-turns at the reduced speed, and the security of up to ten parts."

"Out of curiosity, what percentage of your customers opt for this?"

"Ninety percent."

"Huh. I guess people ran the numbers and it made sense. $500, but no more, huh. That's comforting to know I won't end up owing more than that."